// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_H_
#define FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_H_

#include <gtk/gtk.h>

#include "flutter/shell/platform/linux/public/flutter_linux/fl_dart_project.h"
#include "flutter/shell/platform/linux/public/flutter_linux/fl_view.h"

#include "flutter/shell/platform/embedder/embedder.h"

G_BEGIN_DECLS

/**
 * FlRendererError:
 * Errors for #FlRenderer objects to set on failures.
 */

typedef enum {
  FL_RENDERER_ERROR_FAILED,
} FlRendererError;

GQuark fl_renderer_error_quark(void) G_GNUC_CONST;

G_DECLARE_DERIVABLE_TYPE(FlRenderer, fl_renderer, FL, RENDERER, GObject)

/**
 * FlRenderer:
 *
 * #FlRenderer is an abstract class that allows Flutter to draw pixels.
 */

struct _FlRendererClass {
  GObjectClass parent_class;

  /**
   * Virtual method called when Flutter needs #GdkGLContext to render.
   * @renderer: an #FlRenderer.
   * @widget: the widget being rendered on.
   * @visible: (out): the GL context for visible surface.
   * @resource: (out): the GL context for resource loading.
   * @error: (allow-none): #GError location to store the error occurring, or
   * %NULL to ignore.
   *
   * Returns: %TRUE if both contexts were created, %FALSE if there was an error.
   */
  gboolean (*create_contexts)(FlRenderer* renderer,
                              GtkWidget* widget,
                              GdkGLContext** visible,
                              GdkGLContext** resource,
                              GError** error);

  /**
   * Virtual method called when Flutter needs OpenGL proc address.
   * @renderer: an #FlRenderer.
   * @name: proc name.
   *
   * Returns: OpenGL proc address.
   */
  void* (*get_proc_address)();

  /**
   * Virtual method called when Flutter needs a backing store for a specific
   * #FlutterLayer.
   * @renderer: an #FlRenderer.
   * @config: backing store config.
   * @backing_store_out: saves created backing store.
   *
   * Returns %TRUE if successful.
   */
  gboolean (*create_backing_store)(FlRenderer* renderer,
                                   const FlutterBackingStoreConfig* config,
                                   FlutterBackingStore* backing_store_out);

  /**
   * Virtual method called when Flutter wants to release the backing store.
   * @renderer: an #FlRenderer.
   * @backing_store: backing store to be released.
   *
   * Returns %TRUE if successful.
   */
  gboolean (*collect_backing_store)(FlRenderer* renderer,
                                    const FlutterBackingStore* backing_store);

  /**
   * Virtual method called when Flutter wants to composite layers onto the
   * screen.
   * @renderer: an #FlRenderer.
   * @layers: layers to be composited.
   * @layers_count: number of layers.
   *
   * Returns %TRUE if successful.
   */
  gboolean (*present_layers)(FlRenderer* renderer,
                             const FlutterLayer** layers,
                             size_t layers_count);
};

/**
 * fl_renderer_start:
 * @renderer: an #FlRenderer.
 * @view: the view Flutter is renderering to.
 * @error: (allow-none): #GError location to store the error occurring, or %NULL
 * to ignore.
 *
 * Start the renderer.
 *
 * Returns: %TRUE if successfully started.
 */
gboolean fl_renderer_start(FlRenderer* renderer, FlView* view, GError** error);

/**
 * fl_renderer_get_view:
 * @renderer: an #FlRenderer.
 *
 * Returns: targeted #FlView or %NULL if headless.
 */
FlView* fl_renderer_get_view(FlRenderer* renderer);

/**
 * fl_renderer_get_context:
 * @renderer: an #FlRenderer.
 *
 * Returns: GL context for GLAreas or %NULL if headless.
 */
GdkGLContext* fl_renderer_get_context(FlRenderer* renderer);

/**
 * fl_renderer_get_proc_address:
 * @renderer: an #FlRenderer.
 * @name: a function name.
 *
 * Gets the rendering API function that matches the given name.
 *
 * Returns: a function pointer.
 */
void* fl_renderer_get_proc_address(FlRenderer* renderer, const char* name);

/**
 * fl_renderer_make_current:
 * @renderer: an #FlRenderer.
 * @error: (allow-none): #GError location to store the error occurring, or %NULL
 * to ignore.
 *
 * Makes the rendering context current.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_make_current(FlRenderer* renderer, GError** error);

/**
 * fl_renderer_make_resource_current:
 * @renderer: an #FlRenderer.
 * @error: (allow-none): #GError location to store the error occurring, or %NULL
 * to ignore.
 *
 * Makes the resource rendering context current.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_make_resource_current(FlRenderer* renderer,
                                           GError** error);

/**
 * fl_renderer_clear_current:
 * @renderer: an #FlRenderer.
 * @error: (allow-none): #GError location to store the error occurring, or %NULL
 * to ignore.
 *
 * Clears the current rendering context.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_clear_current(FlRenderer* renderer, GError** error);

/**
 * fl_renderer_get_fbo:
 * @renderer: an #FlRenderer.
 *
 * Gets the frame buffer object to render to.
 *
 * Returns: a frame buffer object index.
 */
guint32 fl_renderer_get_fbo(FlRenderer* renderer);

/**
 * fl_renderer_present:
 * @renderer: an #FlRenderer.
 * @error: (allow-none): #GError location to store the error occurring, or %NULL
 * to ignore.
 *
 * Presents the current frame.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_present(FlRenderer* renderer, GError** error);

/**
 * fl_renderer_create_backing_store:
 * @renderer: an #FlRenderer.
 * @config: backing store config.
 * @backing_store_out: saves created backing store.
 *
 * Obtain a backing store for a specific #FlutterLayer.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_create_backing_store(
    FlRenderer* renderer,
    const FlutterBackingStoreConfig* config,
    FlutterBackingStore* backing_store_out);

/**
 * fl_renderer_collect_backing_store:
 * @renderer: an #FlRenderer.
 * @backing_store: backing store to be released.
 *
 * A callback invoked by the engine to release the backing store. The
 * embedder may collect any resources associated with the backing store.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_collect_backing_store(
    FlRenderer* renderer,
    const FlutterBackingStore* backing_store);

/**
 * fl_renderer_present_layers:
 * @renderer: an #FlRenderer.
 * @layers: layers to be composited.
 * @layers_count: number of layers.
 *
 * Callback invoked by the engine to composite the contents of each layer
 * onto the screen.
 *
 * Returns %TRUE if successful.
 */
gboolean fl_renderer_present_layers(FlRenderer* renderer,
                                    const FlutterLayer** layers,
                                    size_t layers_count);

/**
 * fl_renderer_wait_for_frame:
 * @renderer: an #FlRenderer.
 * @target_width: width of frame being waited for
 * @target_height: height of frame being waited for
 *
 * Holds the thread until frame with requested dimensions is presented.
 * While waiting for frame Flutter platform and raster tasks are being
 * processed.
 */
void fl_renderer_wait_for_frame(FlRenderer* renderer,
                                int target_width,
                                int target_height);

G_END_DECLS

#endif  // FLUTTER_SHELL_PLATFORM_LINUX_FL_RENDERER_H_